Coho Salmon

kwṓx̱weth; sthímiya

Oncorhynchus kisutch

Identification Tips:

Adults
• Distinct black spots on top, but not bottom lobe of tail fin (top and bottom spotted on Chinook)
• Base of gums on lower jaw is white (black in Chinook)
• Male spawners deep red with lower head black and strongly hooked jaw
• Female spawners are less vividly coloured

Juveniles
• White leading edge on dorsal fin
• White leading edge followed by thin black line on anal fin
• Fins often orange tinted
• Leading anal fin rays are longer than rest (all similar in Chinook)
• No spots on dorsal fin (Cutthroat and Rainbow have them)

Conservation Status:

British Columbia	Canada		Natureserve
	COSEWIC	Species at Risk Act
Not at Risk (Yellow List)	Not at Risk	None	G4, S4

Information Source: BC Conservation Data Centre: http://a100.gov.bc.ca/pub/eswp/

Life History:

• Many coastal fish rear in freshwater for 1 full year; many interior fish for 2
• Most migrate to sea between April and June
• Some migrate directly to estuary at emergence from gravel
• Most spend 18 months at sea before returning to spawn
• Some males return after 6 months at sea to spawn as small bodied 'Jacks'
• Juveniles use one of two feeding strategies: holding small territories in flowing water where they forage on drifting invertebrates or actively patrolling and foraging over large areas
• Most populations spawn between September and December, but may be as late as March in the Fraser Valley
• Spawn at night

Habitat:

• Often spawn in very small tributary streams (1-2 m width)
• Juveniles rear in pools and glides of small streams
• Overwintering juveniles move into deep cover, often in off-channel habitats or headwater beaver ponds
• Adults eat herring and other fish
• Fraser River and other Coho from southern BC use inshore waters while at sea
• Northern stocks venture much further offshore.

Range:

British Columbia
• Large and small rivers along entire coast
• Most populations spawn and rear within 250 km of coast
• Some populations ascend 500 km or in more large rivers
• In Fraser to headwaters of Thompson Rivers and sporadically to Prince George

Global
• North Korea, and northern Japan to Siberia
• Southern California to northern Alaska and east along arctic coast to Mackenzie River, NWT.

Comments:

• There are approximately 2,600 Coho stocks in BC
• 29 are extirpated; 214 at high risk but the status of about 1,200 is unknown
• Interior Fraser Coho are assessed as Threatened by COSWEWIC (scientific body) but the government has declined to list them under the Species at Risk Act
• Lower Fraser Coho are in decline due to habitat loss and degradation; low oxygen levels make much of their habitat unusable during the prime rearing season.

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Primary Information Source:
McPhail, J.D. 2007. The Freshwater Fishes of British Columbia. University of Alberta Press. Edmonton, Alberta.